Abstract: 8844 Issued October 1992 8844 Analogue Inputs The analogue inputs (IN HI, IN LO, REF HI and REF LO) are differential inputs. They respond only to the voltage across them an not their voltage with respect to the power supply. However, no input must be higher than 0.5V below the positive supply or lower than 1.0V above the negative supply. (Note that the DPM generates its own negative supply of approximately 2.8V below V-). The COM pin (9) is a convenient method of establishing the c ...